Surface and catalytic properties of V2O5-TiO2/SO42- catalysts for the oxidation of methanol prepared by various methods

被引:27
作者
Zhao, H. [1 ,2 ]
Bennici, S. [1 ]
Shen, J. [2 ]
Auroux, A. [1 ]
机构
[1] Univ Lyon 1, CNRS, Inst Rech Catalyse & Environm Lyon IRCELYON, UMR 5256, F-69626 Villeurbanne, France
[2] Nanjing Univ, Sch Chem & Chem Engn, Lab Mesoscop Chem, Nanjing 210093, Peoples R China
关键词
V2O5-TiO2/SO42-; Adsorption microcalorimetry; Acidity; Methanol selective oxidation; Dimethoxymethane; OXIDE MONOLAYER CATALYSTS; OXYGEN-CHEMISORPTION; REDOX PROPERTIES; SELECTIVE OXIDATION; ACIDITY; DIMETHOXYMETHANE; REDUCTION; VANADIA; V2O5/TIO2; ALUMINA;
D O I
10.1016/j.molcata.2009.04.011
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The influence of the preparation method on the surface and catalytic properties of sulfated vanadia-titania catalysts has been studied. V2O5-TiO2/SO42- (VTiS) catalysts with 25 wt% V2O5 and 0.2-6.5 wt% S were prepared by co-precipitation, sol-gel and mechanical grinding methods and calcined at 723 K in air. The structural properties were characterized by O-2 chemisorption and laser Raman spectroscopy (LRS). The surface acidity was determined by the techniques of NH3 adsorption microcalorimetry and pyridine adsorption infrared spectroscopy (FT-IR). Catalytic tests of oxidation of methanol to dimethoxymethane (DMM) were performed at atmospheric pressure in a fixed-bed micro-reactor. The Raman spectra revealed that vanadia existed in the form of a crystalline V2O5 phase. The results of ammonia adsorption of microcalorimetry showed a much lower heat of adsorption for samples with high content of SO42-. Meanwhile, pyridine adsorption of FT-IR showed that both Lewis and Bransted acid sites were present on the surface of all VTiS catalysts. The catalytic performance was also influenced by the preparation methods. VTiS-CP catalyst, prepared by co-precipitation, exhibited the highest DMM yield with a DMM selectivity of 86% for 61% methanol conversion at 423 K. (C) 2009 Elsevier B.V. All rights reserved.
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页码:28 / 34
页数:7
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